93 predicted 2 · 8 · 18 · 32 · 22 · 9 · 2

Neptunium, Np, element 93

Actinide· Period 7· f-block

Configuration [Rn]5f46d17s2

Atomic weight
237Da
Phase
solid
Density
20.2g/cm³
Melting point
917.15K 644 °C
Boiling point
4,447K, predicted 4,174 °C
Electronegativity
1.3

Radioactive metallic transuranic element, belongs to the actinoids. Np-237, the most stable isotope, has a half-life of 2.2*10^6 years and is a by product of nuclear reactors. The other known isotopes have mass numbers 229 through 236, and 238 through 241. Np-236 has a half-life of 5*10^3 years. First produced by Edwin M. McMillan and P.H. Abelson in 1940. Description from mendeleev.

Back to the table
The outermost shell: the valence electronsThe inner shellsThe nucleus One bead for each electron, on the ring of its shell, counted from the nucleus out. The rings turn at their own pace; the model is Bohr's picture of the atom, which places electrons in shells but not on true orbits.

Atomic properties

4 of 5 fields have a value for neptunium

Atomic weight The standard atomic weight. For an element with no stable isotope, the mass of its longest-lived isotope.
237Da
Source: mendeleev
Electron configuration
[Rn]5f46d17s2
Source: mendeleev
Electron configuration in full The electron configuration with the noble-gas core written out.
1s22s22p63s23p63d104s24p64d104f145s25p65d105f46s26p66d17s2
Source: Worked outfrom electron configuration
Electrons in each shell Counted from the electron configuration, from the first shell outward.
2 · 8 · 18 · 32 · 22 · 9 · 2
Source: Worked outfrom electron configuration

No data uncertainty of the atomic weight.